Does anybody know how the EUA process actually works? Several mundane and trivial questions, but I just want to know...

1. How do the upgrades actually run? Is it exactly (or a close approximation to) 72 hours in advance of each specific flight? Or is it three nights before?

2. If my upgrade doesn't clear at the gold EUA window, will I have a shot when the computer runs the silver EUA's, or is my only chance at checkin/at the gate?

TIA.